I'm writing the Density Lab test for the UT Invitational this October. Based on y'all's experiences in this event, what have been some of the best (i.e. most creative and challenging) labs you've seen? I'm having trouble coming up with something that isn't too difficult for Division B or too expensive right now.

University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

At 2019 NC states there was a lab where you calculated the density of shaving cream. You sprayed some foam on a paper towel and sucked up a given amount using a syringe and calculated that density, then compressed the syringe a given amount and calculated that density. It was pretty bad because trying to compress the syringe and measure its mass at the same time is hard. Piedmont squirted foam all over my partner, too. It was an accident though.

At 2019 NC states there was a lab where you calculated the density of shaving cream. You sprayed some foam on a paper towel and sucked up a given amount using a syringe and calculated that density, then compressed the syringe a given amount and calculated that density. It was pretty bad because trying to compress the syringe and measure its mass at the same time is hard. Piedmont squirted foam all over my partner, too. It was an accident though.

Yeah that same lab happened at nationals. Some other pretty basic and cheap labs for the event I've seen would include:
Density of like a Lego thing and then determining if it would float or not.
Trying to get as many pennies as possible to float on a piece of foil without tipping.
The shaving cream one aforementioned.
A straw or cylindrical device with one end sealed and trying to get it to sink to a certain depth.
Trying to put as much weight in a 3D shape that has an opening that can be sealed, Cylinder would be most easy to get although I think seeing one as a pyramid may be challenging and fun, then the team that puts the most weight in the shape and it floats wins.
A density column would be really easy for competitors and cheap.
Also, for any lab how much time you give really can make it easier or harder.

how do you practice the "lab" part of the event? I've always been doing good in the tests but I am bad at the lab part, and I saw that the lab part is now 50 percent or more of your score(before it was 25%)

how do you practice the "lab" part of the event? I've always been doing good in the tests but I am bad at the lab part, and I saw that the lab part is now 50 percent or more of your score(before it was 25%)

What I did is I found some hard lab problems from different tests and modified them. I also did lab parts in different tests. Most of the problems in the lab portion are similar so you can use the same method to solve them.